Peppermint Oreo Jello Salad

Dissolve gelatin in boiling water as per directions on package. Add cold water and peppermint extract. Chill until slightly thickened, about 1-1/2 hours. Measure 1-3/4 cups gelatin; pour into a 5x9 inch loaf pan and chill about 5 minutes. Blend Cool Whip into the remaining gelatin. Carefully spoon 1/3 of the creamy mixture into the pan. Sprinkle with half the cookie crumbs. Repeat these 2 layers and spoon the remaining creamy mixture on top. Chill until firm, about 4 hours. Unmold and garnish with additional whipped topping and cookie crumbs, if desired.